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MEA 200

Exam 2 Study Guide
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A water molecule is formed when two hydrogen atoms covalently bond with one hydrogen atom. The oxygen atom has 3 pairs of electrons in the outer shell. What's weird is that both hydrogen atoms bond with only ONE of those 3 pairs creating an asymmetric molecule.

The bond angle between the two hydrogen atoms is 105, rather than the bond angle of a symmetric molecule, which is 180 degrees.

The fact that these two hydrogen atoms are on the same side of the molecule, that side is biased with a more positive charge (because of the nuclei of the hydrogen atoms).

The other side of the molecule (without the hydrogen atoms) is biased with a more negative charge.
Explain how the unique asymmetric structure of the water molecule results in a dipolar electrical distribution of charges on the molecule.
Even though the net charge on the water molecule is 0, the dipolar charge distribution creates a polar molecule.
What is the net (i.e., positive minus negative) charge of a water molecule?
intermolecular bonds that form between water molecules and join them molecules together.
What are hydrogen bonds and how are they associated with the structure of the water molecule?
Hydrogen bonds are the result of the dipolar structure of the water molecule and the fact that the negative side of one molecule is electrostatically attracted to the positive side of another molecule.

They are the single unifying bond that accounts for all the properties of water.
How do the hydrogen bonds result from the dipole structure of a water molecule and cause the unique properties found in water (e.g., surface tension, dissolving power, thermal properties, existence of water in liquid form at normal earth temperatures, etc.)?
Covalent and ionic bonds join atoms together to form molecules.

Hydrogen bonds on the other hand, bond one molecule to another.
How do hydrogen bonds differ from the chemical bonds (covalent and ionic)?
Temperature is the direct measure of the average kinetic energy of the molecules that make up a substance (the more kinetic energy, the higher the temperature).
Define temperature.
Heat is the energy transfer from one body to another due to differences in temperature.
Define heat.
One calorie of heat will raise the temperature of one gram (g) of liquid water by one degree Celsius (C), and defines the gram calorie.
What is the definition of a calorie (cal)?
Liquid, Gas, Solid
What are the 3 states of matter for H2O?
The freezing point would be -90 and the projected boiling point would be -68C. If this were true, water would exist as a gas at normal earth temperatures.

*Water has a very high freezing and boiling point compared to other substances due to the polarity of the molecules, which allows water molecules to bond with each other and exist in liquid form at normal Earth temperatures.
If the structure of the water molecule was symmetric, what is its estimated freezing and boiling temperatures as projected by plots of other molecules with similar structures?
The ability of a substance to absorb heat without a large rise in temperature.

Absorbed heat is used to break the bonds and change the physical state rather than create kinetic energy and raise the temperature.
Define heat capacity in terms of heat absorption.
The amount of heat required to raise the temperature of 1 gram of liquid water by 1 degree Celsius is 1 calorie.

The heat capacity of ice and vapor is half that of liquid water.
Define heat capacity in terms of raising the temperature.
The heat asbsorbed by the pool water or the ocean is used to break hydrogen bonds and is less available to raise the kinetic activity of the water and the temperature doesn't rise much.

Concrete or land mass doesn't have hydrogen bonds. All the absorbed heat is converted into kinetic energy and the temperature increases.
Use heat capacity to explain why the air temperature range, between winter and summer extremes, is much smaller over the ocean than over land. Why is the concrete area around a swimming pool so much hotter than the water in the pool, if they both receive the same solar radiation?
Latent heat is hidden in the sense that added calories do not affect the temperature.
What is latent heat?
It takes 80 calories per gram to change water from solid (ice) to liquid (water).
Latent Heat of Melting
It takes 540 cal/g to turn water into a vapor.
Latent Heat of Vaporization (or Condensation if Cooling)
The process by which water changes from a liquid to a gas or vapor
Evaporation
When ice turns directly into water vapor without first transitioning into a liquid
Sublimation
Rapid change of water into steam
Evaporation
A measure of the actual amount of water vapor in air compared to the saturation value of that air if both have the same temperature.

If air is only holding half of the water it is capable of holding for a given temperature, it is ½ saturated and its RH (relative humidity) is 50%.
Define RH and explain what, for instance, 25% RH means.
The rate of evaporation is directly dependent upon the degree of saturation and only indirectly dependent upon temperature.
To what is the humidity of air relative?
By one of two ways:

1- By holding the amount of water vapor constant and lowering the temperature of the air

2- By holding the air temperature constant and evaporating more water vapor
How does unsaturated air reach the dew point?
The temperature at which unsaturated air is cooled to saturation by cooling alone- without adding additional water vapor.

Another way to describe the degree of saturation of air--> Low RH has a low DPT
What is the dew point temperature?
o You determine the maximum saturation value of water at the same given temperature and then use the RH equation.
o RH = [(Amount of Water Vapor in the Air)/Saturation Value of the Air at the Same Temperature)] X 100
How do you find the dew point temperature from the Table of Air Saturation values given in class?
The human body uses evaporative cooling (perspiration) as the primary mechanism to rid itself of waste heat.

The rate at which perspiration evaporates on the skin under humid conditions is lower than under arid conditions.

Because humans perceive a low rate of heat transfer from the body the same as a higher air temperature, the body experiences greater distress of waste heat burden at a lower temperature with high humidity than at a higher temperature at lower humidity.
Why is it humans can overheat under conditions of high heat and high humidity (i.e., R.H. > 60%)? What retards evaporation?
Leave it in the sun all day and you will be left with 34.7 grams of salt residue→ 34.7 g salt residue in 1000 g of water→ 34.7 ppt (parts per 1000)
For a salinity of 34.7 parts per thousand (ppt), approximately how many grams of "salt residue" will be found in 1 kg (1000 g) of seawater?
o Sodium (Na+)
o Magnesium (Mg++)
o Calcium (Ca++)
o Potassium (K+)
What are the six major ionic constituents in seawater? List by sign of ionic charge.
Regardless of the total concentration (i.e., the total salinity), the relative proportions of the major ionic constituents of seawater are constant.
What is the Rule of Constant Proportions?
Sodium is always 30.61% of the total salinity (total ion concentration_ of seawater no mater what, and chloride is always 55.04%, etc.

Knowing the concentration of one of the solutes allows you to determine the others.
How can the "rule of constant proportions" be used to determine seawater salinity?
Salinity can be measured by only ONE of the constituents, usually chloride, which is the most abundant. This is the official definition used to determine salinity and is done using the following empirical relationship:

• S(ppt)=1.80655 x CL (ppt)
• CL = Chlorinity
How can chlorinity be used to determine seawater salinity?
All ions have a net charge, measure this charge

Salinity is expressed as a ratio of conductivity in a "real-world" sample to a standardized sample.

Conductivity is directly proportional to both salinity and temperature, to measure salinity, temp must be heals constant, usually at 20 C.
How can conductivity be used to determine seawater salinity?
all halogen ions in the seawater, not just the chlorine
What is chlorinity a measure of?
standard value for salinity of the ocean is 35 ppt (or 35 g of salt in 1 kg of seawater)
What is the "standard salinity" value for the ocean?
Mass (in grams, g) per unit volume in cubic centimeters, cm3)
What is the definition of density?
Changes in density will either be the result of changes in the mass, or changes in the volume of a substance

CHECK THIS ANSWER
What are the dimensions of density used in oceanography?
Density of pure water (zero salinity) is directly proportional to pressure (P) and inversely proportional to temperature (T), for T greater than or equal to 4 C-->

DENSITY prop to P, 1/T (for T greater than or equal to 4 C),

Which we would read as "Density is directly proportional to P and/or inversely proportional to T, for temperatures greater than or equal to 4 C."

Therefore, an increase in pressure would increase DENSITY, and an increase in temperature would decrease DENSITY
For freshwater, what is the proportionality relationship of density to temperature and pressure?
The density of seawater has the same pressure and temperature relationships as fresh water but, with the addition of "salt", its mass is increased, so the density of seawater also is directly proportional to salinity (S), and this is for any T; i.e.,

DENSITY prop to P, 1/T, S (for any T).
For seawater, what is the additional proportionality relationship of density to salinity?
Freshwater or any other substance that reaches its maximum density at a higher temperature than its freezing temperature, it behaves in an abnormal manner so, we say, it exhibits a "density anomaly".
When fresh (zero salinity) water is cooled, the maximum density of the water is reached at a higher temperature than the freezing temperature. What are these two temperatures for fresh water, and how do they change for water with salinities greater than zero?
Seawater salinities are all greater than 24.7 ppt, so no density anomaly exists for seawater. Therefore, everywhere in the OCEAN, density will always be inversely proportional to temperature
Why do we call the fact that maximum density is reached at a higher temperature than the freezing point a "density anomaly"? Why does this anomaly no longer exist for salinities greater than about 25 ppt?
4C--> once you cool the basin water to 4 C, only the surface BL cools to the freezing temperature after stable conditions are reached
What conceptually, therefore, is the temperature of the water below the surface as ice freezes on the surface?
Most dense water is on top of the less dense water, which creates an unstable condition.

The heavier water sinks to the bottom, seeking its own desnity, replacing the deeper water, which then rises to the top.

These vertical convection currents are characteristic of unstable conditions.
How does the change of water density with depth affect the stability of the vertical water column?
Unstable Conditions→ density increases with increasing depth

•Dense water on top of less dense water
•Vertical convection current created, characteristic of unstable conditions

Stable Conditions→ density increases with increasing depth

Neutral→ water density is constant with depth
What is the difference between neutral, stable and unstable stability conditions, and in which will vertical convection occur?
1. The 6 C water temp. is higher than the temp. of maximum density, so: Density prop 1/T

2. Heat is lost through the surface

3. Boundary layer temp. decreases

4. Density increases

5. Unstable conditions and vertical convection are established and persist until the temp. of the entire basin reaches 4 C, the temp. of maximum density of fresh water.

6. Any further cooling at the surface BL will only create less dense water, because for temperatures lower than 4C, Density prop T, and stable conditions are created.

7. One convection stops, only the temp. of the BL is cooled below 4 C.

8. Thereafter, the thin BL will quickly lose heat and reach a temperature of 0 C and, after an additional 80 cal/g of latent heat of fusion is lost from this BL, ice will freeze on the surface
Use an understanding of the density anomaly discussed earlier, and of the stability conditions, to explain the process of freezing ice on a fresh water lake.
Because at 4 C we are at maximum density, so for temperatures lower than that, Density prop T.

Once you cool the basin water to 4 C and stable conditions are reached, only the surface BL cools to the freezing temperature
Why is the water temperature no lower than 4 C a few feet below the ice at the moment when ice freezes on the lake (freshwater) surface?
4 C

--> remember, once you cool the basin water to 4 C, only the surface BL cools to the freezing temperature after stable conditions are reached
In regards to bodies of water with salinities < 25 ppt:

In particular, at what temperature will the water beneath the ice be when ice first freezes for these salinities?
No density anomaly exists for seawater (S > 24.7 ppt), cooling at the surface BL will ALWAYS result in unstable conditions and convective overturn

For seawater (S > 24.7 ppt), the entire body of water must be decreased to the freezing temperature
How is the process of freezing ice on the surface of water with salinities > 25 ppt, different from that for salinities < 25 ppt ?
Vertical convective currents?

In a lake, when the basin is cooled to 4C, stable conditions persist, and only the BL continues to cool and ultimately freeze.

CHECK THIS ANSWER!
Why is the temperature of the water below newly frozen ice on the ocean (which has a salinity of about 35 ppt) lower than the temperature of water at the same depth below newly frozen ice on a fresh water lake?
The freezing temperature of seawater is much lower than freshwater, but equally important;

Seawater has no density anomaly, so its entire water mass must be cooled to the freezing temperature, while the entire water mass in freshwater must only be cooled to 4 C (then its BL cools to 0 C).
In what ways do the freezing temperature and the vertical stability condition of this ocean water explain this lower temperature?
temperature slope or gradient with depth
Thermocline
density slope or gradient with depth
Pycnocline
salinity slope or gradient with depth
Halocline
constant temperature with depth
Isothermal
constant density with depth
Isopycnal
constant salinity with depth
Isohaline
• Τemperature is more important than salinity in determining the density profile in the equatorial region (with a very strong permanent thermocline)

• Tropical latitudes- a 5 C increase in the temperature at tropical latitudes has an effect on density that is some three times larger than a 5 C increase in temperature at higher latitudes
At which latitude does temperature have the largest affect on density?
salinity is more important than temperature at higher latitudes.
At which latitude does salinity have the largest affect on density?
They are probably influenced equally by temperature and salinity making the thermocline there more seasonal (formed in summer, broken in fall, for example)
How are temperate regions influenced by salinity and temperature profiles?
Used to obtain Lmax

Lmax is about 0.5 micrometers, and that there are three major divisions of the solar spectrum

UV (ultra-violet) portion at wavelengths less than 0.4 micrometers

Visible portion between 0.4 and 0.7 micrometers

IR (infra-red) portion at wavelengths greater than 0.7 micrometers
What feature of the electromagnetic spectrum does Wein's displacement law define, and how is it related to the temperature of a radiating body?
0.4-0.7
What are the upper and lower wavelength limits of the Visible portion of the solar energy spectrum?
UV ->wavelengths less than 0.4
IR ->wavelengths more than 0.7
In which parts of the solar energy spectrum do the Ultra-violet (UV) and Infra-red (IR) portions reside?
NOT REALLY SURE....

1. ozone (O3) and oxygen (O2) primarily absorb UV radiation and parts of the violet band of the visible portion of the solar spectrum;

2. carbon dioxide, methane, clouds, CFC's and water vapor absorb most of the IR radiation and parts of the red band of the visible spectrum.
Which wavelengths of visible light are least attenuated (absorbed) in water? Which are most attenuated?
Qs - Solar Radiation Flux primarily in the visible range of the spectrum (gain to ocean)
Qb - Back Radiation Flux all in the IR range of the spectrum (loss to ocean)
Qe - Evaporative Heat Flux (loss to ocean)
Qc - Sensible Heat Flux by Conduction (annually and on an ocean-wide average, a loss to ocean)
What are the definitions and dimensions of the heat flux terms Qs and Qb?
Short wave radiation, primarily in the visible range of the spectrum, will penetrate our atmosphere and be reflected or absorbed by the surface of the earth (water or land). If it is reflected it will pass back out of our atmosphere and will NOT warm the earth as part of the Greenhouse Effect.

If the short wave radiation is ABSORBED it must be re-radiated. But, because the earth is so cold compared to the sun, it will be RE-RADIATED as IR, and IR will not pass directly out of the atmosphere (i.e., the wavelength has been converted). This re-radiated IR from the earth's surface will be absorbed by the gases in the atmosphere which, in turn, will re-radiate it also as IR, with some of that radiation being directed back toward the earth.

This temporary "retention" of short wave radiation from the sun (by absorption and re-radiation, thereby changing its wavelength to IR) is the key concept of the Greenhouse Effect.

Note, finally, that the solar radiation initially absorbed by the gases in the atmosphere ALSO WILL CONTRIBUTE to the Greenhouse Effect, because the gases will also re-radiate IR.
In general, describe the Greenhouse Effect.
*IR

Temporary "retention" of short wave radiation from the sun (by absorption and re-radiation, thereby changing its wavelength to IR)
Greenhouse Effect: To what general wavelength must this short-wave radiation be converted before it can be effectively retained in the atmosphere?
ozone (O3) and oxygen (O2) primarily absorb UV radiation and parts of the violet band of the visible portion of the solar spectruM

carbon dioxide, methane, clouds, CFC's and water vapor absorb most of the IR radiation and parts of the red band of the visible spectrum.
What atmospheric gases are most important to this process, and how do they interact with these radiant energies at different wavelengths?
Not really, the reflection of light back into space—largely by clouds, ice, etc.—does not much affect the basic mechanism; this light, effectively, is lost to the system.
Does reflection of solar energy play any part in the Greenhouse Effect?
Total: 33C

→• WATER VAPOR: 16 C
• Clouds: 8 C
• Carbon dioxidE: 7 C
•Methane: 2 C
For how many TOTAL DEGREES rise in air temperature does the Greenhouse Effect actually account, and which of the gases in the air has the LARGEST EFFECT?
• Sensible heat flows in a direction along a temperature gradient from high temperature (source) to low temperature (sink)

• A very inefficient process

• The process of conduction of sensible heat is molecule to molecule (one heated molecule in contact with another molecule transmits heat kinetically to that molecule, which in turn transmits its heat kinetically to another molecule, etc.)
By what process is heat moved during conduction, and why is it called sensible heat?
• Conduction=Qc prop dT/dz

• Defines the temperature gradient and Qc.

• Qc will be directly proportional to the difference in temperature between the source and the sink (dT) and inversely proportional to the distance over which the heat flows (dz).
Heat conduction is directly proportional to the temperature gradient dT/dz - what does this mean?
VERTICALLY

• Vertical gradient (along the z-axis)

• dz is the thickness of the thin air-sea boundary layer (lower-most portion of the atmosphere & upper-most portion of the ocean)
In what direction across the air-sea boundary does sensible heat move?
Conductive heat flows down a gradient from hot to cold.

If the air is colder than the water across the air-sea BL, Heat will flow via conduction from water to the air:

• The air BL will increase in temp. and become less dense, establishing unstable conditions
• Warmer, less dense air rises, creating vertical convection currents
• Cooler more dense water lost from surface sinks and is replaced by 30 C water from below, because the loss of heat from the water BL, which decreases the temp. and increases the water BL density, creating unstable conditions and vertical convection.

If the air is warmer than the water, the heat will flow via conduction from the air to the water:

• The air BL will decrease in temp. and become more dense, creating stable conditions and no convection currents in the air
• The gaining of heat in the water BL causes the temp. to rise and become less dense, stable conditions are established, no convection current created
Describe the transfer of sensible heat via conduction across the ocean surface in regards to the temperature gradient between the air and the water.
Conductive heat flows down a gradient from hot to cold.

If the air is colder than the water across the air-sea BL, Heat will flow via conduction from water to the air:

• The air BL will increase in temp. and become less dense, establishing unstable conditions
• Warmer, less dense air rises, creating vertical convection currents
• Cooler more dense water lost from surface sinks and is replaced by 30 C water from below, because the loss of heat from the water BL, which decreases the temp. and increases the water BL density, creating unstable conditions and vertical convection.
Why is heat most efficiently transferred across the ocean surface when the air is colder than the water?
• Sensible heat flows in a direction along a temperature gradient from high temperature (source) to low temperature (sink)

• The process of conduction of sensible heat is molecule to molecule (one heated molecule in contact with another molecule transmits heat kinetically to that molecule, which in turn transmits its heat kinetically to another molecule, etc.); a very inefficient process
By what process is heat moved during conduction, and why is it called sensible heat?
No→

Qe prop L & E→ Degree of air saturation with water vapor controls the amount of evaporative heat flux Qe that occurs

• Other factors include wind speed and air/water temp.
• There is a direct proportional relationship of Qe to L and E.
• L is the latent heat of evaporation
• E is the total amount of evaporation
Does air temperature ALONE determine whether evaporation (E) takes place?
• The air, into which Qe is transferred, rises and as it cools, the relative humidity increases
• At very high altitudes (10 to 12 km) the air reaches saturation and further cooling occurs
• With further cooling the WATER VAPOR CHANGES PHASE BACK TO A LIQUID AND THE LATENT HEAT (NOW OF CONDENSATION) IS RELEASED TO WARM THE AIR AT THAT HIGH ALTITUDE
• The liquid water then falls back to earth as precipitation, P (rain, snow, sleet, etc.).
Latent heat and liquid water are extracted from the ocean during evaporation and enter the atmosphere together in the form of water vapor (i.e., the gaseous form of H2O).

When and by what process is this latent heat actually released to warm the atmosphere?

What happens to the water?
The rate of heat gained by ocean = The rate of heat lost from ocean
Define the heat budget of the ocean.
• Qs - Solar Radiation Flux
• Qb - Back Radiation Flux
• Qe - Evaporative Heat Flux
• Qc - Sensible Heat Flux by Conduction
List the four principle processes responsible for transferring heat across the boundary between the ocean and the atmosphere.
• Qs - Solar Radiation Flux primarily in the visible range of the spectrum (gain to ocean)

• Qb - Back Radiation Flux all in the IR range of the spectrum (loss to ocean)

• Qe - Evaporative Heat Flux (loss to ocean)

• Qc - Sensible Heat Flux by Conduction (annually and on an ocean-wide average, a loss to ocean)
Of the four principle processes responsible for transferring heat across the boundary between the ocean and the atmosphere, which are considered losses from and which are gains to the ocean? What are their relative rates?
Heat gained = Heat lost

Qs (100%) = Qb(41%)+Qe(53%)+ Qc (6%)

--> Qc = heat lost by ocean
--> Qs = heat gained by ocean
Write the Heat Budget equation of the ocean in terms of the four principle processes.

*Remember the sign of the conduction term????
• Because of differences in the rotational velocity of the earth at high and low latitudes

• Any object or fluid with a mass (m) and a velocity (v) moving on the earth will be deflected by the Coriolis Effect (CE).
How does the earth's rotation cause the CE?
• In the N. Hemisphere, the earth rotates counter-clockwise, and the CE will be deflected to the right

• In the S. Hemisphere, the earth rotates clockwise, and the CE will be deflected to the left
In which direction, relative to a moving object, does the CE act in each hemisphere, and what effect does this have on the object?
Latitude and Speed
The CE is directly proportional to what two things?
Yes, at the equator, and increases with increasing latitude, maximum is at the poles
Is the CE ever equal to zero?
The rate of fresh water gained by ocean area = rate of fresh water lost by ocean area

E = P

or

E - P = 0.
Define the concept of a water budget.
***The convergence of the NE and SE Trades towards the ITCZ

1. E>P in the Trade Wind Region

• Because the moist air has been moved out of the region before it can change phase back to a liquid and fall as precipitation there.

2. P>E at the ITCZ

• Water evaporated (E) in the trade wind regions rise at the same time the atlantic ocean converges toward the ITCZ.
• By the time it reaches the ITCZ it has cooled to saturation and changes phase back to a liquid and falls as precip. So that P>E at the ITCZ.
Why is E minus P (written E-P) defined as the Net evaporation at any particular place in the ocean? E is evaporation and P is precipitation of water (both measured in grams, or in centimeters of water).
1. Low average surface salinity where E>P→ trade wind region

2. High average surface salinity where P>E→ ITCZ
If you look at the average E-P distribution by latitude in the Atlantic Ocean, where would you expect to see: the lowest average surface salinity; the highest average surface salinity?
WEATHER→ what you walk outside of your home to observe -- very short term

CLIMATE→ what you discern by looking at world weather records spanning from a few to many years
What is the difference between weather and climate?
High Pressure Cells→

In the N. Hemisphere, ridge in the jet stream causes air to flow in a clockwise (anit-cyclonic) and creates a high pressure cell in which this air sinks toward the ground because the higher pressure warms the air and lowers its relative humidity.

Low Pressure Cells→

N. Hemisphere, trough in jet stream causes air to flow in a counterclockwise (cyclonic) direction, the air rises and creates low pressure in the center which cools the air and raises the relative humidity, These low pressure centers are usually associated with cloudy and stormy weather.
In the Northern Hemisphere, sinking air is associated with what kind of pressure cell? What about rising air
High pressure→ cloclwise (anticyclonic)
Low Pressure→ Counter-clockwise (cylonic)
The Coriolis effect will cause the air in each of these cells to flow in what direction?
1. Warm fronts are caused by a warm mass of air moving over an existing colder mass of air→

•the boundary between these two masses is what is known as a warm front
•produces long periods of rain but NOT violent storms

2. Cold fronts are caused by a cold mass of air moving into a region already occupied by a mass of warm air.

•Usually moves quickly forcing warmer air up to higher altitudes
•Creates low pressure thunderstorms and other violent weather patterns that move along the frontal boundary and pass quickly through a region
How do warm and cold fronts differ, and which usually results in the most violent storms?
The interaction of the ocean with the coastal land masses can result in twice yearly monsoons (large scale systems, seasonal variation) and twice daily sea breezes and land breezes (small scale systems, daily variation), both of which are the result of differential heating of the land and the water
Contrast and compare NE & SW Monsoons in the Indian Ocean and Land and Sea Breezes on coastlines.
1. Atmospheric component of El Niño and involves an oscillation in surface air pressure between the tropical eastern and the western Pacific Ocean waters

2. Low atmospheric pressure tends to occur over warm water and high pressure occurs over cold water, in part because of deep convection over the warm water.

3. El Niño episodes are defined as sustained warming of the central and eastern tropical Pacific Ocean.

4. This results in a decrease in the strength of the Pacific trade winds, and a reduction in rainfall over eastern and northern Australia.
What is El Nino - Southern Oscillation (ENSO), and how does it affect our climate and weather?
1. Higher levels of carbon dioxide in the ocean is causing an alarming lowering of pH

2. Colder waters that were upwelled along the coastline (water that is essential for bringing nutrients back to the surface from below the thermocline) also is now bringing more acidic waters that are devastating animals with calcium carbonate shells.
What do we mean by acidification of seawater and what is the cause?
• Trade Winds and Prevailing Westerlies
What winds are the primary driving force of the Atlantic Ocean currents?
Balance of Vortices???

Increased Coriolis Effect?
Why does the Gulf Stream in the North Atlantic have a much larger volume transport than the comparable Brazil Current in the South Atlantic?
•Ekman assumed that a homogenous water column was set in motion by wind blowing across its surface and, because of the CE, the top-most layer moved 45 degrees to the right of the surface wind direction. The surface layer, moving as a thin lamina, then sets the layer beneath it in motion, which also is subject to deflection to the right by the CE.
According to Ekman, when the wind blows on the ocean surface, in what direction and angle, relative to the wind, does the top most layer ("lamina") of the surface water move? Why?
•Wind energy is passed through the water column from the surface down, with each successive layer being deflected more to the right and having a lower velocity than the layer above (as shown in in the figure to the right) as energy is dissipated.
•This continues until all the momentum imparted by the wind at the surface has been distributed to all the lamina, and there is no longer any motion.
How is the Ekman Spiral created and what does it represent ?
•The depth of frictional influence is the depth at which motion ceases is called the Depth of Frictional Influence (usually about 100 - 150 m).

•The net motion of the water being moved in the Ekman spiral ( ET) includes the average velocity (direction and speed) of all the lamina in the spiral.

•Imagine a spar float (a long, narrow float that remains vertical in the water) with a length exactly that of the depth of frictional influence, that is made to float with NONE of its length being out of the water (so that it will not be moved by the wind).
What is the depth of frictional influence, how deep does it normally extend, and how is the Ekman Transport related to it?
•important consequence of the ET is the vertical upward movement (upwelling) of water that results from the transport

This upwelled water comes from below the surface (usually deeper than the thermocline - a very substantial barrier to the vertical movement of water), and is one of the few ways in which water is exchanged upward across the thermocline
How does the Ekman Transport cause coastal upwelling (the vertical upper-ward movement of water), and what are the favorable wind directions (relative to the coastline) for upwelling to occur? What about coastal downwelling?
•NE Trade Winds north of the equator and the SE Trade Winds south of the equator converge at an angle toward the equator [ITCZ, which "straddles" the equator at an angle].

•The ET set up by these converging winds causes a horizontal DIVERGENCE of surface water (generally, to a depth of more than 100 m) toward the northwest and southwest, respectively, AWAY from the equator.

•This divergence of water at the surface brings water from below 100 m which upwells to replace those surface waters
How does the Ekman Transport cause equatorial upwelling?
A horizontal ocean current that exists, by definition, when the down-slope component of gravity - the result of a slight slope in the sea surface - is balanced by the Coriolis force

•High pressure to the right of the flow in the northern hemisphere
• High pressure to the left of the flow in the southern hemisphere
• Examples: Gulf Stream, the Kuroshio Current, the Agulhas Current, and the Antarctic Circumpolar Current

At the moment that v becomes constant (with CE and G in balance and vectorally opposite in direction) we have, by definition, a Geostrophic Current.
YOU NEED TO REMEMBER THIS DEFINITION.
What is a Geostrophic Current?
•"A mass in motion will remain in motion with a constant velocity (constant speed and direction) so long as the forces acting on it are balanced".

→The corollary, therefore, is:

•"A mass in motion will have a curved path, or will accelerate or decelerate, if the forces acting are it are NOT balanced."
How can Newton's first law of motion be used to explain and understand the formation and maintenance of the Geostrophic current that results from this balance?
•Determine DEN in the same way as I did above (write the inequalities directly on your exam paper as I did above),
•Then write "least dense" above the station column that had the least dense water (in this case above Station A).
•Then remember that the sea surface will ALWAYS slope down from least dense to most dense, so actually draw the sea surface (as shown in the cross-sectional view above, in this case, from A to B).
How can you determine sea surface height at, and sea surface slope between, two hydrographic stations in the ocean using a knowledge of the average water density at each station?
• The slope will decrease from the station with higher average density to the station with lower average density
In what direction does the sea surface slope if you know that one station has a lower average density than the other?
Knowing which hemisphere you are in tells you if the CE will cause a deflection of 90 deg. to the right OR the left of the current velocity.

Northern Hemisphere→
•CE will be 90 deg. to the right of the current velocity, current will flow OUT OF THE SCREEN.

Southern Hemisphere→
•CE will be 90 deg. to the left of the current velocity, current will flow INTO THE SCREEN
If the sea surface slope has already been determined, why do you need to know which hemisphere you are in before the direction of the geostrophic current can be determined?
This current, since it is relative to the cross-section between the two stations, will always be running perpendicular to that cross-section.
At what angle, relative to the cross-section between the two stations, does the current flow?
•Increase density means increased volume
•Slope will decrease from higher density to lower density
•Slope and CE drive Geostrophic currents
How can increased density near the surface drive the deep ocean currents?
•Defined as conservative because they are changed only by advection
•Oxygen and carbon dioxide may be changed by chemical or biological processes and, therefore, cannot reliably be used to trace the advection of a water mass.
What are conservative and non-conservative properties of a fluid?
We actually trace these water masses using a plot of temperature and salinity (called a T-S Diagram- These water masses have 'characteristic' features that identify them visually on the T-S Diagram and make them easy to recognize.
How can ocean temperature and salinity (both conservative properties) be used in the tracing of water masses under the ocean surface using a T-S Diagram?
S Shape, Lowest Salinity, No coupled-pair values

AAIW, when present in the ocean, always shows up on the T-S Diagram with the S-shape shown on the right and with the minimum salinity in the water colum.

•Current that forms primarily in the S. Hemisphere summer by mixing low-salinity surface waters with melting Antarctic ice.

AAIW is not traced by a coupled-pair of temp. and salinity values, but by its minimum salinity in the water column.
What distinguishes Antarctic Intermediate Water (AAIW) on the T-S Diagram; i.e., does it have a fixed T and S like North Atlantic Deep Water (NADW), wherever it is found?
Currents on the western side of an ocean basin, such as the Gulf Stream, are faster, narrower and extend to greater depths than currents on the eastern boundary.
What are the key differences between currents on the western side of an ocean basin (like the Gulf Stream) and currents on the eastern boundary?
•Wind Stress - Trade Winds and Prevailing Westerlies create a clockwise (CW) vorticity that is equal on both sides of the basin.

•Frictional Stress - The eastern & western boundaries of the basin both induce a weak counter-clockwise (CCW) frictional vorticity (set up as a resistance to the flow of water) that is also equal on both sides of the basin.

•Coriolis effect (CE) - The Coriolis effect, because it increases with latitude, creates a different vorticity on the two sides of the basin. On the western side, the northward flowing current is subject to an increasing CE deflection, which induces a CW vorticity, while on the eastern side, the southward flowing current is subject to a decreasing CE deflection, which induces a CCW vorticity. Note, therefore, that the CE rotational directions are opposite on the two sides of the basin.
What three rotational (vorticity) forces, when balanced, cause this intensification in currents on the western side of the ocean basin (like the Gulf Stream)?
Would the intensification of currents on the western side of the ocean basin (like the Gulf Stream) occur if the earth did not rotate around it's axis?
The Kuroshio Current
In addition to the Gulf Stream, which of the following currents also are intensified: Kuroshio, Brazil, Canary or California?
Oxygen and carbon dioxide may be changed by chemical or biological processes and, therefore, cannot reliably be used to trace the advection of a water mass.

*Remember that hydrogenous calcium carbonate can be precipitated several kilometers below the surface, and when that happens, the amount of carbon dioxide dissolved in the seawater will change
Why are dissolved oxygen and carbon dioxide considered 'non-conservative properties of a fluid'?
Vertical Circulation!!!!

Upwelling!!!!

Density-driven currents due to differences in temperature and/or salinity at the ocean surface that can cause density changes that drive these subsurface water masses
Define Thermo-Haline Currents.
•Because the temperature and salinity of subsurface water masses changes only as a result of advection, we can use temperature and salinity to trace that advection, and we call temperatue and salinity conservative properties of a fluid.

•New water mass (w/new salinity and temp. values) advects (flows) into, and displaces, the original water from that location.

•We can trace this new water mass by its temp. and salinity signature.
Why are temperature and salinity at deeper depths defined as "conservative properties of a fluid?"
they are narrow, fast-moving, and extend to a great depth
Why do the Western intensified currents have the ability to transport more volume?
Rotating rings of very warm water with warm- or cold-water cores, found on both sides of a western boundary current such as the Gulf Stream.
What are Eddies?
Eddies form because the Gulf Stream can move laterally at a rapid pace.

Partly as a result of its contact with the edge of the continental shelf and slope, the current may meander.

Usually, these meanders intensify so much that they break off, creating a rotating ring of what was very warm Gulf Stream water around a stationary core of cool or warm water.
How are these eddies formed from meanders in the Gulf Stream?
COLD-CORE EDDY→
•cool shelf water is trapped within a CCW flowing meander when it 'pinches off'
•will be on the OCEAN-SIDE of the gulf stream.

WARM-CORE EDDY→
•warm Sargasso Sea water is trapped within a CW flowing meander when it 'pinches off'
•will be on the LAND-SIDE of the gulf stream.

The DIRECTION OF ROTATION of the rings around these eddies is the same as that of the meanders just before it breaks off.
The water inside the core of each of these eddies comes from what two locations, and on what sides of the Gulf stream are COLD-CORE and WARM-CORE eddies each found after their formation -- in what direction do their rings rotate?
They do not have the energy source required to keep up the rotation and will eventually "spin down" due to internal friction from the water.

•Warm-Core Eddies are quick to spin down and are quickly dispersed into the surrounding ocean.
•Cold-Core Eddies last longer because they are in deep ocean water and don't spin down as fast as warm-core eddies to the left of the current
How long do each of these eddies last before they lose their identity - what causes them to disappear?